coccinelle: add test on malloc error check.

This patch adds a coccinelle code check on SCMalloc, SCCalloc and
SCStrdup and other memory handling functions. It verifies that the
error checking is made.

qa/coccinelle/malloc-error-check.cocci

@@ -0,0 +1,44 @@
+@malloced@
+identifier x;
+position p1;
+identifier func =~ "(SCMalloc|SCStrdup|SCCalloc|SCMallocAligned|SCRealloc)";
+@@
+
+x@p1 = func(...)
+
+
+@inlinetested@
+identifier x;
+position p1;
+statement S;
+identifier func =~ "(SCMalloc|SCStrdup|SCCalloc|SCMallocAligned|SCRealloc)";
+@@
+
+if ((x@p1 = func(...)) == NULL) S
+
+@istested@
+identifier x;
+position malloced.p1;
+statement S1, S2;
+identifier func =~ "(SCMalloc|SCStrdup|SCCalloc|SCMallocAligned|SCRealloc)";
+@@
+
+x@p1 = func(...)
+... when != x
+(
+if (unlikely(x == NULL)) S1
+|
+if (x == NULL) S1
+|
+if (x != NULL) S1 else S2
+|
+BUG_ON(x == NULL)
+)
+
+@script:python depends on malloced && !istested && !inlinetested @
+p1 << malloced.p1;
+@@
+
+print "Structure malloced at %s:%s but error is not checked." % (p1[0].file, p1[0].line)
+import sys
+sys.exit(1)